The connection between Helen Mirren, 69, strong, fearless, embracing life with ever greater vigour and starring in the newly released Woman in Gold, and Mary Elizabeth Jennifer Rachel Abergavenny Slocombe, possibly born in the 1920s, once employed as a senior member of staff in the Grace Brothers department store, may not be obvious. However, the historic sitcom character, notoriously single but for the cat referred to routinely as “my pussy”, could easily act as chief witness in Mirren’s accusation that the sexism of the 1970s was “worse than the 1940s or 50s. It was horrible.”

Are the 70s guilty as charged? Mirren was passing judgment in an interview in a national newspaper last week. In the 1970s, she was in her 20s and 30s and her extraordinary talent had become obvious; she was seen as a posh hippy bohemian not least because of her tattoo – then, a sure sign of the subversive counterculture and not the kite mark of the masses as it is now – when she made an appearance on Michael Parkinson’s television chatshow. He asked how someone in their 20s, so “sluttishly erotic”, could be regarded as a serious actress: wouldn’t her “big bosoms” detract from her performance?

Forty years later it might seem like an Alan Partridge parody but then it was far from unusual, and gave Jimmy Savile his cover. “That decade, after the sexual revolution but before feminism, was perilous for women,” Mirren said last week. “Men saw that as a sort of “Oh fantastic! We can fuck anything, however we like, whenever we like. They’re up for grabs, boys!”

Mirren is right that the rules of carnal engagement had altered, equality had yet to catch up and decades of conditioning for men and women clung like giant barnacles on behaviour, hampering real change. The pill had “liberated” women, so men no longer had to pay the price for sex with a shotgun marriage and a lifetime as a breadwinner. The flight from commitment had begun. Yet, at the same time, women who did “go all the way” were still deemed “bikes”, a cause for alarm. In 1973, Erica Jong wrote the very funny and perceptive Fear of Flying. Married woman Isadora Wing goes to Europe in search of the “zipless fuck” – commitment-free sex. Today, to some, that may seem like the formula for the average good night out. Then, it was revolutionary. Wing is confounded by men who refuse to understand the terms of this new egalitarianism. She says: “It was the same old jargon… the same old fifties lingo in disguise. There is no such thing as rape. You ladies ask for it.”

Confusion reigned to the point that it was assumed that, in bed, what women wanted must be the flipside of what men desired: how wrong. The clitoral orgasm was revealed. “Think clitoris,” women were instructed, but as they didn’t want to upset their husbands (if they were heterosexual), and females were, and are, inclined to blame themselves, the 70s saw a flood of “how to” manuals. The Joy of Sex et al, arguably unread by those who had most to learn, all became bestsellers. The sexually assertive woman was timidly validated, but she was still in a daze.

Jane Firbank was then a twentysomething editor of the monthly sex magazine Forum. She fell into bed because, she said, “I was so overwhelmed that someone wanted me. It never occurred to me to say no.” At the same time, in Ruth Carter Stapleton’s The Gift of Inner Healing, the good wife was one who greeted her husband, home from a hard day’s work, as if he were Jesus. In contrast, in the 1977 hit film Looking for Mr Goodbar, a woman who likes one-night stands meets a grisly death, while the coverage of Peter Sutcliffe’s crimes as the Yorkshire Ripper reinforced the message that women paid a price if they transgressed from traditional “feminine” behaviour.

Parkinson v Mirren in 1975: a now notorious encounter.

Mirren is right on the impact of the sexual revolution, but wrong on chronology. The 70s was the decade when feminism took hold – and perhaps that’s why sexism became still more marked. Ms magazine was launched in the US and Spare Rib in the UK. Germaine Greer’s The Female Eunuch asked of her readers: “The old process must be broken – what will you do?” She also said that she didn’t go much on “Pom” lovers. One had suggested: “Let’s pretend you’re dead.”

It was the decade in which the first women’s strike for equality in the US was held (26 August 1970). “Don’t cook. Starve a rat,” was one slogan. The private had become public. Helen Reddy won a Grammy for the song I Am Woman. And in Britain, legislation was passed to tackle discrimination and enforce equal pay, while refuges to help those fleeing domestic abuse mushroomed, as did rape crisis centres. Paradoxically, at a time of burgeoning female liberation, it was also the reign of Mrs Slocombe, a popup from a naughty 50s postcard with a nasty injection of patronising “know your place “ misogyny. (One that, as Mirren suggests, also saturates the words “sassy” and “feisty”).

Mrs Slocombe, played by Mollie Sugden, appeared in the popular BBC sitcom Are You Being Served? It encapsulated the weird whirlpool of changing social attitudes, challenges to male power and female doubts about the value of sexual liberation that failed to deliver independence, freedom from domesticity or a route to female desire.

Slocombe, a divorcee with wigs of changing hues, was portrayed as being sex-mad but unthreatening to men because she was over 40, and therefore obviously out of action. Each week, she was ridiculed for her age, appearance, weight and love of her “pussy”. In one scene, Captain Peacock, a retail colleague, beckons her. “I do not respond to a man’s finger,” she says.

In the 70s, this sexist nudge, nudge, wink, wink humour was endemic in comedies such as TheBenny Hill Show, with its dirty old milkman pursuing very young women who, for some unfathomable reason, would run around suburbia in bikinis. On the Buses featured the shortsighted, less than glamorous Olive, who was the butt of all the “face like a back of a bus” jokes. The Carry On films happily gorged on innuendo and Barbara Windsor’s body parts. It was an era of dim dolly birds and “real” blokes.

“Spread your legs, enjoy maximum leg-room in the new Pontiac Star Chief” read one US magazine ad, not uncommon in its tone. It passed as normal until the cumulative impact of legislation, changing social norms and a sense of vigilance was sharpened. Today, that vigilance is further honed by social media in sites such as The Everyday Sexism Project. In the 70s, even while Mirren and many other women put up with misogyny or risked accusations of a sense of humour bypass, lessons were being learned.

In Saturday Night Fever (1977), for instance, Tony Manero, the king of the dancefloor and clerk in a paint store, courts his girlfriend Stephanie by trying to rape her in the back seat of a car. Stephanie resists and dumps him. She has a life of her own: female aspiration was overtaking matrimony as a goal. As Barbara Ehrenreich wrote in The Hearts of Men, even in the 70s “boyish in Brooklyn is boorish in more sophisticated boroughs”.

The 70s saw machismo in the cinema writ large: Taxi Driver, The Deer Hunter, Rocky, and Blue Collar – but there was defeat, not defiance in the air. Since then, sexism in Britain has been reduced or driven underground. Men like Parkinson weren’t even aware of the offensiveness of their behaviour; they had lived so long in their own world.

Now, some males, like a young Mirren in the 1970s, are objectified, belittled, stereotyped and ogled not for what they do but how they look. Forty years ago, it was demeaning. It still is – even for Poldark. It’s equality, but not of the sort that counts.